This invention relates to apparatus and methods for mounting components such as hydraulic units within vehicles and more particularly to a vibration transmitting isolator and technique for toollessly mounting a hydraulic unit in a vehicle.
There is a trend in the automotive industry to assemble individual components into a functional unit and then mount that unit in the vehicle. For example, motor driven fluid pumps, accumulators, valving and various sensors may be integrated into a vehicle braking unit. It is necessary that the hydraulic unit is not rigidly attached to the vehicle chassis in order to protect the hydraulic unit and its electronics from shocks and vibrations normally experienced by the vehicle. Additionally in the normal operation of the pump and motor system of the hydraulic unit pulsations are created which must be damped from the chassis to avoid excessive vehicle noise. One problem to be solved is finding a shock mounting packaging arrangement that reduces forces needed for hand assembly processes so they are reasonable for the customer. The package must satisfactorily cushion and retain the hydraulic unit in consideration of life of the vehicle and anticipated vibrational and shock excitation in an environment where corrosive substances and temperature extremes may be encountered. Several braking unit mounting techniques have been used such as in a current packaging concept which involves a sheet metal bracket that holds an automotive component (in this example ABS hydraulic unit) requires isolation to protect the component from vehicle vibration and reduce introduction of vehicle noise from the component. Shock mounting may be achieved by resilient washers interposed between mounting bolts and the vehicle framework, or by integrated resilient dampers pressed into the hydraulic unit housing which support bolts or threaded studs extending from the housing. With this concept, significant customer concern has been expressed at the high press in forces required to assemble hydraulic units into the bracket and there are often customer complaints regarding those high press-in forces as well as ongoing quality problems regarding torquing fasteners supplied as part of component. In one case, because of hydraulic unit geometry such as location of the electronic control unit (ECU) connector, this stamped geometry has small ears which are easily deformed causing quality problems at customer as well as additional preventative costs at bracket suppliers. By eliminating a sheet metal interface to the hydraulic unit and replacing it with more robust studs, this problem could be eliminated. In another case, integrated dampers have the problem that they do not significantly resist rotation about pin axes. This means that the isolator in the hydraulic unit housing begins to turn before a sufficient hold torque can be reached when torquing the nuts during customer assembly. By eliminating the thread and fastener this problem could be eliminated. Often, the distance of the hydraulic unit center of gravity from customer connection points has created a cantilevered mass which amplifies vibrations and causes isolator wear. This creates additional effort in finding adjustments to this packaging technique so that components meet endurance requirement
It is desirable to provide a packaging concept for antilock braking systems, traction control systems or electronic stability program (ABS/TCS/ESP) hydraulic unit connection to a vehicle which provides for ease of customer assembly while robustly retaining and isolating hydraulic unit throughout expected vehicle life.